Download GNSS Implementation in Cellular Modules - U-Blox

Positioning Implementation - Application Note

To get the best possible position fix, set the desired accuracy very small, e.g. 1 m, and the timeout period
duration long. The hybrid positioning feature then runs to the end of the timeout period, and produces the
final, best, output position fix

To get a position estimate with the minimum energy consumption, for maximum battery life, set a large
desired accuracy figure for the hybrid positioning, e.g. 1 km, (see the Figure 24, most likely the AS sensor
position degraded or the GNSS one will be quickly returned if the time spent is below 30s)
u-blox is extremely mindful of user privacy. When a position is sent to the CellLocate® server, u-blox is
unable to track the SIM used or identify the specific device.
See the u-blox AT Commands Manual [1] for the syntax description of AT+ULOC, AT+ULOCCELL,
AT+ULOCGNSS, AT+ULOCIND and AT+ULOCAID commands.
The detailed response provides useful information about the sensor used to estimate the position. When
the sensor reported is “0” this means that the device has been able to calculate the position to sufficient
accuracy immediately by means of the integrated AS Sensor, and has output this immediate position
estimate.
6.3 GNSS sensor setup
The AT+ULOCGNSS command sets up the GNSS sensor for hybrid positioning. It is possible to configure which
aiding types and GNSS systems (refer to section 4) are available to the GNSS sensor. The additional parameters,
listed below, are available for modifying the GNSS receiver behavior. These are strictly related to the GNSS
receiver. The parameters are sent at GNSS power on and are not saved within the receiver. The default values
are the same as those on the positioning chip/module. For values and additional details about their effect refer
to the u-blox Receiver Description document related to the u-blox GNSS receiver [10] [11] [12] [13]:

UBX-CFG-PM2 message configures the power save mode of the GNSS by setting the optimization target flag
in power consumption or in default mode
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UBX-CFG-NAVX5 message configures the minimum number of satellites for navigation, minimum satellite
signal level for navigation and if the initial fix must be 3D
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UBX-CFG-NAV5 configures the static hold mode: allows the navigation algorithms to decrease the noise in
the position output when the velocity is below a pre-defined "Static Hold Threshold". This reduces the
position wander caused by environmental issues such as multi-path and improves position accuracy
especially in stationary applications. By default, static hold mode is disabled

UBX-CFG-SBAS enable/disable: SBAS (Satellite Based Augmentation Systems) is an augmentation technology
for GNSS, which calculates GNSS integrity and correction data with RIMS (Ranging and Integrity Monitoring
Stations) on the ground and uses geostationary satellites (GEOs) to broadcast GNSS integrity and correction
data to GNSS users. The correction data is transmitted on the GNSS L1 frequency (1575.42 MHz), and
therefore no additional receiver is required to make use of the correction and integrity data

UBX-CFG-ITFM configures Jamming/Interference monitor: enables/disables the indicator, sets the antenna
type, broadband jamming detection threshold and continuous wave jamming detection threshold
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UBX-CFG-GNSS configures the GNSS system channel sharing configuration and activation for a multi-GNSS
receiver. For details about valid configurations see the u-blox Receiver Description document related to the
u-blox GNSS receiver [10] [11] [12] [13]
UBX-13001849 - R15
Early Production Information
Hybrid positioning and CellLocate®
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